Fluid-pressure brake.



UNITED STATES PATENT OFFICE.

HENRY H. WESTINGHOUSE, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO THE VVESTING-HOUSE AIR BRAKE COMPANY, OF PITTSBURG, PENN SYLVANIA, A CORPORATION OF PENNSYLVANIA.

FLUID-PRESSURE BRAKE.

Specification of Letters Patent.

Patented Nov. 20, 1906.

To 00% whom it may concern:

Be it known that I, HENRY H. WESTING- HOUSE, a citizen of the United States, residing in Pittsburg, county of Allegheny, and State of Pennsylvania, have invented a certain new and useful Improvement in Fluid- Pressure Brakes, of which the following is a specification.

This invention relates to automatic fluid pressure brakes, and has for its object to provide an improved valve device having a su plemental piston cooperating with a supp mental reservoir or other source of fluid-pressure for .closing the exhaust from the brakecylinder after the triple valve has been moved under an increase of train-pipe pressure to open said exhaust, and thereby secure a graduated release of the brakes.

With the present standard triple-valve device, as is well known, after an application of the brakes has been made there is no means for grading down the brake-cylinder pressure. Consequently Where the brakes are applied with greater pressure than desired it is necessary to entirely release the same and then reapply at the desired pressure, thus wasting a large amount of compressed air. My invention is designed to overcome this objectionable condition and in general comprises in addition to the customary triplevalve device a supplemental piston actuated by pressure from a supplemental reservoir or other source of fluid-pressure for moving the valve to close the brake-cylinder exhaust after the triple valve has been moved under a slight increasein train-pipe pressure to open said exhaust after an application of the brakes, whereby the brake-cylinder exhaust will be successively opened and closed each time that a slight increase is made in trainpipe pressure and the brake-cylinder pressure may be graded down to any point desired.

My invention also comprises means whereby the movement of the valve device itself controls communication from the supplemental reservoir or other source of fluid-pressure to one side of the supplemental piston and from the opposite side of said piston to the exhaust.

. In the accompanying drawings, Figure 1 is a diagram showing an air-brake equipment embodying my improvement; Fig. 2, a sectional view of the triple-valve device illustrated'in Fig. 1 Fig. 3, a section of the valvechamber and supplemental-piston chamber, taken on the line 00 0c of Fig. 4; Fig. 4, a horizontal section of said chamber, showing the arrangement of ports within the valve-seat, and Fig. 5 a face view of the main slide-valve of the triple-valve device.

According to the construction shown the air-brake equipment as applied to a car comprises the trai11-pipe 1, branch pipe 2, leading to the triple-valve device 3, which is connected to the auxiliary reservoir 4, the pipe 7, leading to the brake-cylinder 5, and the pipe 8, leading to the supplemental reservoir 6.

The triple-valve device comprises a casing having the usual train-pipe passage 9 leading to cap-chamber 10, piston-chamber 11, containing piston 12, valve-chamber 13, containing piston-stem 15, main slide-valve 14, and graduating-valve 16. In the valve-seat are located the usual brake-cylinder port 17, leading to pipe 7, and the exhaust-port 18,while the slide-valve is provided with the usual graduating or service port 19 and exhaustcavity 20. In addition to this standard construction and in accordance with my improvement I provide a supplemental-piston chamber 21 and piston 22, preferably located in line with the triple-valve chamber, as shown, although it may be located in any other position desired and adapted to oper-. ate upon a valve to close the brake-cylinder exhaust. One end of the piston-stem 23 extends by a neat fit through the dividing-partition 24 and engages the main slide-valve 14 by means of an extension 25, while the other end of said stem is guided in a recess in the cap 26, which contains the piston-chamber 2 1.

Additional ports 27 and 28 lead from the respective ends of said supplemental-piston chamber to the slide-valve seatand there 00- operate with the respective ports 29, leading to the pipe 8 of the supplemental reservoir, and 30, leading to the exhaust, to the atmos phere, or other chamber or space of lower pressure than the auxiliary reservoir, the slide valve being provided with the corresponding additional cavities 32 and 33. Another port 34, containing check-valve 35, leads from the triple-valve piston-chamber to the supplemental-reservoir pipe 8 for the purpose of charging the said supplemental reservoir to standard normal pressure from the train-pipe when the triple valve is in release position.

The operation of my improved device is as follows: The system is charged with air under pressure from the main reservoir in the usual way, the triple-valve device moving to full-release position, in which the brake-cylinder port 17 is connected to the exhaustport 18 through the usual exhaust-cavity 20 in the main slide-valve and the auxiliary reservoir being supplied from the train-pipe through the usual feed-gro ove around the triple-valve piston. The air irom the auxiliary reservoir and valve-chamber Will also leak slowly through the partition 24 around the stem 23 at the same time that air is supplied to the supplemental reservoir through port 34, check-valve 35, and pipe 8 and to the supplemental-piston chamber 21 through ports 29 and 27, the cavity 32 serving to connect these ports in full-release position of the valve. The additional port 30 is closed by the slide-valve in this position, so that there is no chance for a leak to the atmosphere from i the supplemental-piston chamber. All parts of the valve device and reservoirs will thus be charged to standard normal pressure.

When a reduction in train-pipe pressure is made for a service application of the brakes,

the predominating pressure in the auxiliary reservoir carries the triple-valve piston back tov service position and moves the slide-valve to cut off brake-cylinder exhaust and open the service-port 19 to the brake-cylinder port 1 17 in the usual way. This movement 01'' the slide-valve also closes the port 27, thereby. cutting oii communication from the supplemental-piston chamber and. the normal stand- .1 ard pressure is retained in the supplemental reservoir by means of the check-valve 35. 1 Air irom the auxiliary reservoir then flows to the brake-cylind er, charging the same in the usual way until the piston moves to lap posi- 1 tion and closes the graduating-valve.

If now it be desired to grade down the brake-cylinder pressure a certain amount without entirely releasing the same, a slight increase is made in train-pipe pressure suflicient to start the triple piston and slidevalve toward release position. haust-cavity 20 reaches such position as to When the main ex- 1 partially open the brake-cylinder port 17, the i cavity 32 connects supplementahreservoir port 29 with port 27, leading to the chamber at one side of the supplemental piston 22, while the other cavity 33 connects ports 28 and 30, thereby opening communication from the chamber on the opposite side of the supplemental piston to the exhaust, and it is in this position that the parts of the triple-valve device are indicated in Figs. 2 and 3 of the drawings.

The high pressure which has been retained in the supplemental reservoir now acting on the upper side of the supplemental piston,

while the lower side of the same is open to the exhaust, causes the supplemental piston to move the slide-valve and triple piston. back to lap position or to a position in which the exhaust from the brake-cylinder is closed. This same movement of the valve also serves at the same time to cut off both ports 27 and 28, leading to the opposite sides of the supplemental piston, thereby permitting the pressure to equalize through the groove 36 between the chambers on the opposite sides of said piston and prevent further movement of the valve. In the meantime the brake cylinder pressure has been reduced by the amount discharged to the atmosphere while the exhaust-port was open.

Further reductions in the brakecylinder pressure may be made in the same manner by further increasing the train-pipe pressure, thereby effecting a grading down of the brakecylinder pressure to any desired point without entirely releasing the brakes. A full release may also be secured at any time by making a considerable increase in train-pipe pressure in the usual way.

The addition of ports 28 and 30 and cavity 33 for momentarily opening communication from the chamber on the lower side oi the supplemental piston to the atmosphere is not absolutely necessary to thesuccessful and practical operation of my improvement, since the high supplemental-reservoir pressure acting on said piston in opposition to the lower auxiliary-reservoir pressure in the lower l from the brake-cylinder at a single graduation will of course depend upon the amount of the increase made in the train-pipe pressure; but even if the wave of increase should be suflicient to carry the triple valve all the way to release position it will be noticed that the ports 29 and 27 are still connected by the cavity 32, so that the supplemental-reservoir pressure will continue to act upon the supplemental piston and cause the movement of the same to close the brake-cylinder exhaust, as before described.

While I have described my improvement as applied to a triple-valve device of the socalled plain type, it will be apparent that the same may also be employed equally well in connection with the quick-action triple valve in which a local venting of the trainpipe is effected in emergency applications of the brakes. It will also be evident that my invention may also be applied to any valve device operating under variations of trainpipe pressure for controlling the exhaust from the brake-cylinder.

Having now described my invention, What I claim as new, and desire to secure by Letters Patent, is

1. In a fluid-pressure brake, the combination with a train-pipe, auxiliary reservoir, brake-cylinder and supplemental reservoir, of a valve device operated by variations in train-pipe pressure for controlling the supply of air to the brake-cylinder and the exhaust from the brake-cylinder, a supplemental piston or movable abutment for actuating said valve device to close the brake-cylinder exhaust, and means operated by an increase in train-pipe pressure to open communication from the supplemental reservoir to one side of said abutment.

2. In a fluid-pressure brake, the combination With a train-pipe, auxiliary reservoir, brake-cylinder and supplemental reservoir, of a valve device having a piston subject to the opposing pressures of the auxiliary reservoir and train-pipe for controlling the supply of fluid to and from the brake-cylinder, a supplemental piston. or abutment for moving said. valve device to close the brake-cylinder exhaust, and means controlled by said valve for admitting fluid from the supplemental reservoir to one side of said abutment.

3. In a fluid-pressure brake, the combination With a train-pipe, auxiliary reservoir, brake-cylinder and supplemental reservoir,

of a valve for controlling the exhaust from the brake-cylinder, a movable abutment operated by train-pipe pressure for moving said valve to open the exhaust, a supplemental piston for actuating said valve to close the exhaust, and means operated by an increase in train-pipe pressure for supplying air from the supplemental reservoir to said supplemental piston.

4. In a fiuid-pressure brake, the combination with a train-pipe, auxiliary reservoir, brake-cylinder and supplemental reservoir, of a valve device and piston operated by variations in train-pipe pressure for controlling communication from the auxiliary reservoir to the brake-cylinder, from the brake-cylinder to the atmosphere, and from the supplemental reservoir to one side of the supplemental piston, and the supplemental piston acting on said-valve device.

5. In a fluid-pressure brake, the combination With a train-pipe, auxiliary reservoir, brake-cylinder and "supplemental reservoir, of a piston and valve device operated by variations in train-pipe pressure and having ports for controlling communication from the auxiliary reservoir to the brake-cylinder, from the brake-cylinder to the exhaust, from the supplemental reservoir to one side of the supplemental piston, and from the opposite side of the supplemental piston to the exhaust, and the supplemental piston acting on said valve device.

6. In a fluid-pressure brake, the combination With a train-pipe, auxiliary reservoir, triple valve, and brake-cylinder, of a device including a supplemental piston for controlling the brake-cylinder exhaust, and means operating upon an increase in train-pipe pressure to supply air from an additional source to said supplemental piston.

7. In a fluid-pressure brake, the combination with a train-pipe, a brake-cylinder, a valve for controlling the release from the brake-cylinder, and a piston subject to variations in train-pipe pressure for operating said valve, of a supplemental piston also acting on said valve to close the brake-cylinder exhaust, and means operating upon an increase in train-pipe pressure to supply'air from an additional source to one side of the supplemental piston.

8. In a fluid-pressure brake, the combination with a train-pipe, auxiliary reservoir, triple valve, and brake-cylinder, of a device including a supplemental piston for controlling the brake-cylinder exhaust, and means operating upon the movement of the triple valve to release position to open communication from a source of pressure to one side of said supplemental piston.

9. In a fluid-pressure brake, the combination With a train-pipe, a brake-cylinder, a valve for controlling the release from the brake-cylinder, and a piston subject to variations in train-pipe pressure for operating said valve, of a supplemental piston also acting on said valve to close the brake-cylinder exhaust, and means operating upon the move ment of the valve to release position to open communication from a source of pressure to one side of said supplemental piston.

10. In a fluid-pressure brake, the combination With a train-pipe, a brake-cylinder, a valve for controlling the release from the brake-cylinder, and a piston subject to variations in train-pipe pressure for operating said valve, of a supplemental piston also acting on said valve to close the brake-cylinder exhaust, said valve having ports for controlling communication from a source of fluidpressure to one side of the supplemental piston and from the opposite side of said piston to the exhaust.

In testimony whereof I have hereunto set my hand.

HENRY H. WESTINGHOUSE.

Witnesses:

R. F. EMERY, JAs. B. l\/IAGDONALD. 

